Water

• What should you be able to describe by the end of the video?

  How to analyze and purify water
• What is potable water?

  Water that is safe to drink
• How does potable water differ from pure water?

  Potable water may contain dissolved solids
• What is the pH of pure water?

  7
• What indicates that a water sample is not pure?

  If the pH is not seven
• How can you check the pH of water?

  Using universal indicator paper
• What does a pH of seven indicate about water?

  It is neutral
• What should you do if the pH of the water is not seven?

  Test for dissolved solids
• What is the first step in testing for dissolved solids in water?

  Weigh an empty evaporating basin
• What happens to the mass of the evaporating basin if dissolved solids are present?

  The mass will increase
• Why does the mass of the evaporating basin increase if dissolved solids are present?

  Crystals form on the basin's surface
• What might still be present in water even if it contains no dissolved solids?

  Dissolved gases
• What is the process of purifying water by distillation?

  Heating water to create vapor, then condensing
• What equipment is used in the distillation process?

  Conical flask and delivery tube
• What happens to water when it is heated in distillation?

  It evaporates and forms water vapor
• What occurs when water vapor enters the cold test tube during distillation?

  It condenses back into liquid water
• What is distilled water?

  Water with no dissolved solids
• What is the pH of distilled water?

  7
• What are the steps to analyze a sample of water for purity?

  1. Check the pH using universal indicator paper.
  2. Weigh an empty evaporating basin.
  3. Fill the basin with the water sample.
  4. Heat the water until it evaporates.
  5. Weigh the basin again to check for dissolved solids.
• What are the steps to purify water by distillation?

  1. Place water sample in a conical flask.
  2. Heat the flask gently with a Bunsen burner.
  3. Allow water to evaporate into vapor.
  4. Collect vapor in a delivery tube.
  5. Condense vapor back into liquid in a cold test tube.